/*
 * Copyright (c) 2009, Hamish Morgan. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the University of Sussex nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package locusts.server.behaviours;

import javax.vecmath.Tuple2d;
import javax.vecmath.Tuple2f;

import javax.vecmath.Vector2d;
import locusts.common.entities.Actor;

/**
 * Steering towards a target point.
 *
 * @author Hamish Morgan Morgan
 */
public class Seek extends AbstractBehaviour {

    protected static final double DEFAULT_MAX_DISTANCE =
            Double.POSITIVE_INFINITY;
    protected Tuple2d target;
    protected double maxDistance;

    public Seek(double weight, Tuple2d target, double maxDistance) {
        super(weight);
        setTarget(target);
        this.maxDistance = maxDistance;
    }

    public Seek(double weight, Vector2d target) {
        this(weight, target, DEFAULT_MAX_DISTANCE);
    }

    public Seek(Vector2d target) {
        super();
        setTarget(target);
        this.maxDistance = DEFAULT_MAX_DISTANCE;
    }

    public void setTarget(Tuple2d target) {
        if (target == null)
            throw new IllegalArgumentException();
        this.target = target;
    }

    public void clearTarget() {
        this.target = null;
    }

    public void setMaxDistance(double maxDistance) {
        this.maxDistance = maxDistance;
    }

    public double getMaxDistance() {
        return maxDistance;
    }

    public Vector2d getSteering(Actor boid) {
        Vector2d steering = new Vector2d();
        if (getWeight() == 0)
            return steering;
        if (target == null)
            return steering;

        double dx = target.x - boid.getX();
        double dy = target.y - boid.getY();
        double d = (dx * dx + dy * dy);
        if (d > maxDistance * maxDistance)
            return steering;

        steering.set(dx * (1 / d), dy * (1 / d));
//        steering.set(dx*(1/d), dy*(1/d));
//
        steering.scale(getWeight());

        return steering;
    }
    
   
    @Override
    public boolean equals(Object obj) {
        if (obj == null) return false;
        if (getClass() != obj.getClass()) return false;
        final Seek other = (Seek) obj;
        if (this.target != other.target &&
                (this.target == null || !this.target.equals(other.target)))
            return false;
        return super.equals(obj);
    }

    @Override
    public int hashCode() {
        int hash = super.hashCode();
        hash = 29 * hash + (this.target != null ? this.target.hashCode() : 0);
        return hash;
    }
}
